FINALLY!!!!! RELIEF FROM IBS WITH DIARRHEA!!!!
I can't believe I've finally found a combination that is working for me without any medication. Maybe it will help you. After reading so much of what many of what you all kindly suggested to me (thank you, thank you!!!!), I believe that IBS-D is caused by gastric dumping in my case most of the time. I have been successful in controlling it (or drastically reducing the number of occurrences) by doing the following:
1. eat oat cereals - oat flakes, oat granola, oat bran, oat & raisins, oat & nuts, oat & cranberries, etc. Must be OATS. Regular cooked oatmeal didn't seem to be helping me.
2. never drink anything with your meals - stop drinking anything about 30 minutes before meals and do not drink anything until about 30 minutes after a meal. If you must drink something, only take very tiny sips of water so you don't choke on your food. This is critical. You can learn to eat without drinking.
3. eat small meals - 6 small meals is much better than 3 regular meals a day
4. after your meals, DO NOT GET UP AND MOVE AROUND FOR AT LEAST 15 MINUTES. If possible, lay back and relax for 30 minutes to let your tummy relax so it does not go into spasms and dump the contents into the intestines. Every time I forget to do this, I immediately head for the bathroom and have diarrhea and lose my entire meal. If I am in a restaurant, I sit back, relax, lounge in my chair, chat with my dinner companions, and wait for at least 15 minutes before even trying to leave the table. If possible I even sit an extra 10 minutes outside the restaurant. I've made it all the way home without having to find a gas station to lose dinner and have not gotten sick when I've gotten home. How wonderful!!!
5. nibble on oat granola bars between meals - adds that extra oats to your diet
6. eliminate sweets, candy, sugars, sodas, ice cream, desserts, etc. 
very hard to do but it helps tremendously
7. eat more protein (but avoid beef), eat any fruits and vegetables you can tolerate, avoid carbs, drink water
I'm feeling better than I have in 6 months, having normal bowel movements with form to them, having very few attacks of diarrhea (I was having 10-20 a day for the past 6 months) and no medicine was helping. 
Hope this helps some of you out there. Take what helps - ignore the rest. I will not stop till I find what works for me since the doctors have been of no help and it looks like they haven't helped any of you either.
Gail 